Security at Watford General Hospital has since been tightened in the building with increased patrols.
A Women and children’s services building was locked down for almost an hour on August 12th.
A spokesperson for Herts Police said: “A woman, aged in her 20s, was later arrested on suspicion of impersonating a doctor.
She has been released on police bail while enquiries continue.”
No name has been given.
The reasons why are unknown, but if charged more details will follow.